| 摘要 |
An electrical control device designed to produce a variable electrical signal proportional to the degree of change of an environmental parameter over a preselected band width. A pair of electrical contacts in a normally spaced apart relation are connected in series between a signal source and the element to be controlled so that the signal is allowed to be transmitted to the element upon the closing of the contacts. This invention operates by using a high frequency interruption of a signal current by means of a pair of opening and closing contacts. One contact is positioned relative to the other by means of an environmental sensing device responding to changes in a particular environmental parameter. The second contact is mechanically coupled to the current responsive device for effecting movement of the second contact away from the first contact when energized to provide a continuous interruption of the signal, where the ratio of the current responsive device's on-time to off-time is proportional to the degree of change of the environmental parameter within the preselected band width.
|
